This book is a great encapsulation of a common traditional understanding of Jewish theology. As Aryeh Kaplan notes in the introduction to the Feldheim edition that I read, this work is notable in its systematic treatment of key Jewish ideas. While it at times is a bit short on arguments, it is quite successful in explaining key Jewish beliefs and showing how these beliefs relate to one another. The English provided in the Feldheim edition is not a literal translation, but rather a sentence-by-sentence translation. This is necessary because the book is written originally in a Hebrew from before the systematization of Modern Hebrew, which, when paired with the philosphical content of the text, can make for difficult reading. The translation is quite clear, however, and the copious notes do a good job at showing the biblical and rabbinic sources that Luzzatto uses to present his points.
The book is divided into four sections- the first being on the 'fundamentals' of God, humankind, and the spiritual realm, the second being on providence, the third on prophecy and the soul, and the fourth on the ways of serving God. The Feldheim edition is concluded with the author's own "An Essay on Fundamentals" which serves as a nice recapping of the key points of the book.
While my own theological views are more modern/liberal than those presented here, I find this book to be of great value to anyone interested in Judaism. Even where it reveals the errors of tradition, I applaud it for doing so clearly, and it provides much to chew on for anyone new to matters of Jewish theology.
My personal lowpoint in reading this book came early in section one, where Luzzatto runs into a paradox. While he writes that God relishes human freedom, he also laments that humankind is not completely free because of Adam's sin and subsequent fall. However, it would seem that God, who supposedly wishes for nothing more than that humankind should serve God freely, could easily either have prevented this fall or lifted humankind back to the previous state of freedom.
On the other hand, the fourth section was my favorite part of the text, providing explanations of various commandments in the Jewish tradition and how they affect our connection to God and the spiritual realm. Because of its connections to extant Jewish practices, I find this section the most relevant of the book, but it would not have the force that it does without the theological beliefs articulated in the first three sections.
Luzzatto's presentation offers a novel way to consider the wishes of the Divine for the world and humankind. Quite often throughout the book, Luzzatto explains a phenomenon of existence by saying something along the lines of 'because the Highest Wisdom saw it fit to do so'. Taking this explanation seriously, we might be encouraged to view the universe and Jewish mitzvot (commandments) not only as expressions of God's morals, but also of God's aesthetics. To live a pious life then is more than being moral, but being beautiful in God's eyes.